1. Field of the Invention
The present invention relates to an optical system for correcting an optical axis, including an optical deflector.
2. Description of the Related Art
FIG. 1 shows a known optical axis correcting system including an optical deflector to which the present invention is directed. This optical system is comprised of a first optical system (afocal optical system) 10, a deflector 20 and an optical convergent optical system 30, in this order from the object side. The deflector 20 deflects a light incident thereupon so that the light incident upon the first optical system 10 can be always converged onto a same point by the convergent optical system 30, even if the optical axis of the light incident on the first optical system 10 is inclined.
However, in the known optical axis correcting system, if the convergent optical system 30 requires strict optical properties (aberration correction), it is difficult to increase the magnification of the first optical system 10 and the deflection angle of the light by the deflector 20, and hence it is difficult to miniaturized the convergent optical system 30. In other words, if the magnification of the first optical system 10 or the deflection angle of the deflector 20 is increased, light is made incident upon the periphery of the convergent optical system 30, thus resulting in a reduced convergence.